1. U5 - Water Water Use & Management

2. Water Use  More than 1 billion people lack access to clean freshwater  Water used for residential, industrial, or agricultural uses  Most water is used for irrigation  Irrigation = watering crops

3. Residential  US avg. person - 80 gal of water per day  ½ (40 gal) used for in home activities –X. drinking, cooking, washing, flushing  Water is treated to make it potable and remove pathogens  Potable = water safe to drink  Pathogens = disease or illness causing organisms

4. Residential Water Usage

5. Water Treatment  1. Filtration – remove trash, debris  2. Coagulation- alum added, forms flocs. Bacteria attaches to flocs and settle at bottom  3. Filtration- sand, gravel, hard coal  4. Chlorination- to prevent bacteria  5. Aeration- air forced to release gases, reduce odor, improve taste  6. Additional – may add fluoride, lime to soften water  7. water pumped to tanks for home use

7. Industrial  19% of water use  Most is used to cool power plants –Water pumped in from local source then pumped back out –Can cause thermal pollution  X. 500,000 L needed to make a car

8. Agricultural  80% of ag. water evaps and never reaches plants  Irrigation – providing plants w/ water from sources other than precipitation  Types – sprinkler, flood, drip

9. Water Management Projects  Dams, river diversions  Usually to bring water to areas where it doesn’t exist  Dam = structure built across river to control flow –Can provide power –Creates reservoirs  Reservoir = artificial lake or river formed behind a dam –Water used for drinking, irrigation, etc.

10. Water Conservation  Agriculture - drip irrigation to save losses from evap, seepage, and runoff  Drip Irrigation = moves small water amounts to plant roots  Industry – recycle cooling and wastewater  Home – low flow toilets, payments to install water saving equipment  Xeriscaping = landscaping to require less water  Copy Page 282 – Table 2 “What Can You Do”

11. Solutions?  1. Desalination = removing salt from salt water –water boiled, steam collected –Very expensive –What do you do w. excess salt?  2. Transporting Water –Moving to areas w/ low amounts of water